Changes in vascular perfusion of the endometrium in association with changes in location of the embryonic vesicle in mares.
Abstract: The equine embryonic vesicle is mobile on Days 12-14 (Day 0 = ovulation), when it is approximately 9-15 mm in diameter. Movement from one uterine horn to another occurs, on average, approximately 0.5 times per hour. Mobility ceases (fixation) on Days 15-17. Transrectal color Doppler ultrasonography was used to study the relationship of embryo mobility (experiment 1) and fixation (experiment 2) to endometrial vascular perfusion. In experiment 1, mares were bred and examined daily from Day 1 to Day 16 and were assigned, retrospectively, to a group in which an embryo was detected (pregnant mares; n = 16) or not detected (n = 8) by Day 12. Endometrial vascularity (scored 1-4, for none to maximal, respectively) did not differ on Days 1-8 between groups or between the sides with and without the corpus luteum. Endometrial vascularity scores were higher (P < 0.05) on Days 12-16 in both horns of pregnant mares compared to mares with no embryo. In pregnant mares, the scores increased (P < 0.05) between Day 10 and Day 12 in the horn with the embryo and were higher (P < 0.05) than scores in the opposite horn on Days 12-15. In experiment 2, 14 pregnant mares were examined from Day 13 to 6 days after fixation. Endometrial vascularity scores and number of colored pixels per cross-section of endometrium were greater (P < 0.05) in the endometrium surrounding the fixed vesicle than in the middle portion of the horn of fixation. Results supported the hypothesis that transient changes in endometrial vascular perfusion accompany the embryonic vesicle as the vesicle changes location during embryo mobility.
Publication Date: 2004-12-01 PubMed ID: 15576822DOI: 10.1095/biolreprod.104.036384Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research investigates the changes in blood flow to the endometrium (lining of the uterus) in correlation with the movement and fixation of the equine embryonic vesicle (small, fertilized embryo in horses). The study discovered that increased blood flow in the uterus accompanies the changing location of the embryonic vesicle during its mobility phase.
Methodology
- The embryonic vesicle in horses is highly mobile between the 12th and 14th day post-ovulation, moving approximately 0.5 times an hour between the two uterine horns. The vesicle becomes fixed between the 15th and 17th day.
- The study was carried out in two parts. Experiment 1 focused on embryo mobility and experiment 2 on embryo fixation.
- In the first experiment, mares were bred and evaluated daily from Day 1 to Day 16. These were split into two groups: one group where the embryo was detected by Day 12 (pregnant mares), and another group where an embryo wasn’t detected.
- In the second experiment, 14 pregnant mares were monitored from Day 13 to six days post-fixation.
Findings
- Through the use of transrectal color Doppler ultrasonography, the researchers were able to track the endometrial vascular perfusion, or blood flow to the uterus, in relation to the presence and movement of the embryonic vesicle.
- The study found no significant differences in endometrial vascularity (measured on a scale from 1 for none, to 4 for maximal) between the two groups or between the sides of the uterus with and without the corpus luteum during days 1-8.
- However, on days 12-16, endometrial vascularity scores were noticeably higher in both uterine horns of the pregnant mares compared with the mares without an embryo.
- In the pregnant mares, an increase in vascularity scores was noted between Day 10 and Day 12 in the horn containing the embryo. The scores were also higher in this horn compared to the opposite one from Days 12-15.
- In the second experiment, endometrial vascularity scores and the number of colored pixels per cross-section of the endometrium were found to be higher in the endometrium region surrounding the fixed vesicle than in the middle part of the horn where the vesicle was fixed.
Conclusion
- The results of this study support the hypothesis of a relation between the movement of the embryo and the transient changes in endometrial blood flow in the mare. This suggests that there is an increased blood supply to the part of the uterus housing the moving or fixed embryo, likely playing a role in supporting embryo growth and development.
Cite This Article
APA
Silva LA, Gastal EL, Beg MA, Ginther OJ.
(2004).
Changes in vascular perfusion of the endometrium in association with changes in location of the embryonic vesicle in mares.
Biol Reprod, 72(3), 755-761.
https://doi.org/10.1095/biolreprod.104.036384 Publication
Researcher Affiliations
- Eutheria Foundation, Cross Plains, Wisconsin 53528, USA.
MeSH Terms
- Animals
- Embryo Implantation / physiology
- Embryonic Development
- Endometrium / blood supply
- Endometrium / diagnostic imaging
- Endometrium / physiology
- Female
- Horses / embryology
- Horses / physiology
- Muscle Contraction / physiology
- Pregnancy
- Pregnancy, Animal / physiology
- Regional Blood Flow
- Ultrasonography, Doppler, Color
Citations
This article has been cited 13 times.- Daghash SM, Yasin NAE, Abdelnaby EA, Emam IA, Tolba A, Abouelela YS. Histological and hemodynamic characterization of corpus luteum throughout the luteal phase in pregnant and non-pregnant buffalos in relation to nitric oxide levels based on its anatomical determination. Front Vet Sci 2022;9:896581.
- Lawson EF, Grupen CG, Baker MA, Aitken RJ, Swegen A, Pollard CL, Gibb Z. Conception and early pregnancy in the mare: lipidomics the unexplored frontier. Reprod Fertil 2022 Jan 1;3(1):R1-R18.
- Yama P, Yadmak C, Sangkate M, Jitjumnong J, U-Krit W, Promsao N, Montha N, Sudwan P, Mektrirat R, Panatuk J, Inyawilert W, Sringarm K, Lumsangkul C, Tapingkae W, Doan HV, Tang PC, Moonmanee T. In Vivo Follicular and Uterine Arterial Indices as an Indicator of Successful Hormonal Stimulation for Inactive Ovaries in Repeat-Breeder Crossbred Dairy Cows Using a Short-Term Progesterone-Based Programme. Animals (Basel) 2022 Jan 25;12(3).
- Swegen A. Maternal recognition of pregnancy in the mare: does it exist and why do we care?. Reproduction 2021 May 5;161(6):R139-R155.
- Ratto MH, Urra F, Silva M. Laterality of Ovulation and Presence of the Embryo Do Not Affect Uterine Horn Blood Flow During the First Month of Gestation in Llamas. Front Vet Sci 2020;7:598117.
- Zampini EG, Gallelli MF, Chaves MG, Neild DM, Gambarotta M, Miragaya MH, Trasorras VL. Uterine and Corpus Luteum Blood Flow Evaluation Prior to Uterine Flushing in Llama Embryo Donors. Front Vet Sci 2020;7:597960.
- Alonso MA, Silva LA, Affonso FJ, Lemes KM, Celeghini ECC, Lançoni R, Carvalho HF, de Arruda RP. Effect of hCG application at different moments of the estrous cycle on corpus luteum and uterine vascularization and serum progesterone concentration in mares. Anim Reprod 2019 Oct 24;16(2):317-327.
- Camacho CA, Estradé MJ, Cazales N, Caballeros JE, Fiala-Rechsteiner SM, Neves AP, Mattos RC. Histomorphometric and vascular changes in equine endometrium after the infusion of conceptus fragments. Anim Reprod 2020 Jun 29;17(2):e20200006.
- Lasheen ME, Badr HM, Kandiel MMM, Abo El-Maaty AM, Samir H, Farouk M, Eldawy MH. Predicting early pregnancy in Egyptian buffalo cows via measuring uterine and luteal blood flows, and serum and saliva progesterone. Trop Anim Health Prod 2018 Jan;50(1):137-142.
- Lakhanpal D, Mohanty TK, Bhakat M, Arunkumar R, Nain D, Baithalu R. Testicular thermoregulation and blood perfusion score as markers of sperm quality in summer-stressed breeding bulls. Trop Anim Health Prod 2025 Sep 30;57(8):419.
- Siemieniuch-Tartanus M. The early pregnancy in mares - What do we still not know?. Vet Anim Sci 2025 Jun;28:100441.
- Bazer FW, Johnson GA. Early Embryonic Development in Agriculturally Important Species. Animals (Basel) 2024 Jun 26;14(13).
- de Castro T, van Heule M, Domingues RR, Jacob JCF, Daels PF, Meyers SA, Conley AJ, Dini P. Embryo-endometrial interaction associated with the location of the embryo during the mobility phase in mares. Sci Rep 2024 Feb 7;14(1):3151.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
